TWI696156B - Overdrive method and timing controller - Google Patents

Abstract

An overdrive method and a timing controller for a liquid crystal display panel are provided. The overdrive method includes the following operations. A frame rate of the liquid crystal display panel corresponding to an overdrive value of the liquid crystal display panel is detected. When determining that the frame rate changes, the overdrive value is correspondingly changed and is then used for driving operation on the liquid crystal display panel.

Description

Overdriving method and timing controller

The invention relates to an overdriving method and timing controller, and in particular to an overdriving method and timing controller for a liquid crystal display panel.

Liquid crystal display is one of the mainstream products in the field of display technology industry. For the liquid crystal display, if the reaction speed of the liquid crystal molecules is too slow during the playback of the dynamic film, it will cause the moving picture to appear blurred. In view of this, the LCD display can use over-driving technology in the playback of dynamic movies to solve the problem of slow response. However, the over-driving technology may affect the display quality under different conditions. For example, when the frame rate changes or the gray scale value changes, there may be a problem that the light intensity changes too much, resulting in a decrease in user experience.

One aspect of the present invention is to provide an overdrive method and timing controller for a liquid crystal display panel, which can improve the image display quality of the liquid crystal display panel when the frame rate changes and the image display quality when the gray scale value changes .

According to the above object of the present invention, an overdriving method for a liquid crystal display panel is proposed. The overdriving method includes: detecting the frame rate of the liquid crystal display panel, which corresponds to the overdrive value of the liquid crystal display panel; And when it is judged that the frame rate changes, the overdrive value is changed accordingly, and the liquid crystal display panel is driven with the changed overdrive value.

According to one or more embodiments of the present invention, correspondingly changing the overdrive value includes: when judging that the frame rate is increased, increasing the overdrive value accordingly; and when judging that the frame rate is reduced, correspondingly decreasing Less than the drive value.

N。 According to one or more embodiments of the present invention, the overdrive value corresponding to the i- th frame after the frame rate is changed is OD _O +[ i (OD _C -OD _O )/ N ], where i is Positive integer, OD _O is the overdrive value before the frame rate changes above, OD _C is the target overdrive value after the frame rate change above, N is the graph that passes when the target overdrive value is reached after the frame rate change above Number of frames, and i

N.

According to the above object of the present invention, another overdriving method for a liquid crystal display panel is proposed. The overdriving method includes: obtaining the corresponding previous gray from the look-up table according to the previous gray level value and the current gray level value of the liquid crystal display panel The overdrive value of the level value and the current grayscale value; the first gain value is determined according to the difference between the previous grayscale value and the current grayscale value; the second gain value is determined according to the current grayscale value; and the overdrive value, the first A gain value and a second gain value are calculated, and then the overdrive value is updated with the calculated result, and the liquid crystal display panel is driven with the updated overdrive value.

According to one or more embodiments of the present invention, the previous gray level value and the current gray level value are positive integers greater than or equal to 0 and less than 2 ^N , and N is 8 or 10.

According to one or more embodiments of the present invention, the difference between the previous gray level value and the current gray level value is less than or equal to 32.

According to one or more embodiments of the present invention, each of the first gain value and the second gain value is greater than 0 and less than or equal to 1.

According to one or more embodiments of the present invention, the second gain value is a concave function, a decreasing function, or an increasing function of the current gray-scale value.

According to the above object of the present invention, another timing controller is proposed. The timing controller is suitable for a liquid crystal display panel and includes a frame rate detection unit and an overdrive value generation unit. The frame rate detection unit is used to detect the frame rate of the LCD panel. This frame rate corresponds to the overdrive value of the LCD panel. The overdrive value generating unit is used to change the frame rate when the frame rate detection unit determines that the frame rate changes and output an overdrive value to drive the liquid crystal display panel.

According to the above object of the present invention, another timing controller is proposed. The timing controller is suitable for a liquid crystal display panel and includes an overdrive value generation unit and an overdrive value adjustment unit. The overdrive value generating unit is used to obtain the overdrive value corresponding to the previous grayscale value and the current grayscale value of the LCD panel from the look-up table, and determine the first gain according to the difference between the previous grayscale value and the current grayscale value The value and the second gain value are determined according to the current gray scale value. The overdriving value adjusting unit is used to calculate the overdriving value, the first gain value and the second gain value, and then update the overdriving value with the result of the operation, and drive the liquid crystal display panel with the updated overdriving value .

110‧‧‧ Frame rate detection unit

120, 310‧‧‧ Overdrive value generating unit

130、320‧‧‧Look-up table

330‧‧‧Overdrive value adjustment unit

Cur‧‧‧Current gray scale value

Pre‧‧‧Previous grayscale value

For a more complete understanding of the embodiment and its advantages, reference is now made to the following description made in conjunction with the accompanying drawings, where: [FIG. 1] is a block diagram of overdrive values generated according to some embodiments of the invention; [FIG. 2] is A schematic diagram of the relationship between the frame number and the overdrive value when the frame rate changes according to some embodiments of the present invention; [Figure 3] is a block diagram generated by the overdrive value according to some embodiments of the present invention; [Figure 4] is based on A schematic diagram of a lookup table in some embodiments of the present invention; [FIG. 5] is a table of correspondences between the difference between the previous gray scale value and the current gray scale value and the first gain value according to some embodiments of the present invention; and [FIG. 6] It is a table of correspondence between the second gain value and the previous gray scale value according to some embodiments of the present invention.

The embodiments of the present invention are discussed in detail below. However, it can be understood that the embodiments provide many applicable inventive concepts that can be implemented in a variety of specific contents. The specific embodiments discussed are for illustration only and are not intended to limit the scope of the invention.

Please refer to FIG. 1, which is a block diagram of generating an overdrive value according to some embodiments of the present invention. The block diagram package shown in Figure 1 The frame rate detection unit 110, the overdrive value generation unit 120 and the lookup table 130 are used for the overdrive processing of the liquid crystal display panel. In some embodiments, the overdrive process of the LCD panel is performed in the timing controller, that is, the frame rate detection unit 110, the overdrive value generating unit 120, and the memory for storing the lookup table 130 are all located in the timing controller in.

The frame rate detection unit 110 is used to receive the frame data, detect the frame rate of the LCD panel accordingly, and send the frame rate data to the overdrive value generating unit 120 according to the detection result. The overdrive value generating unit 120 determines whether the frame rate of the display device has changed based on the received frame rate data. If it is judged that the frame rate of the display device changes, the overdrive value generating unit 120 changes the output overdrive value according to the data in the lookup table 130, and drives the liquid crystal display panel based on the changed overdrive value.

In detail, if it is determined that the frame rate is increased, the overdrive value generating unit 120 generates a new overdrive value based on the data corresponding to the changed frame rate in the lookup table 130, and the new overdrive value is greater than the frame rate change The overdrive value output before. On the contrary, if it is determined that the frame rate is reduced, the overdrive value generating unit 120 generates a new overdrive value according to the data of the corresponding changed frame rate in the lookup table 130, and the new overdrive value is less than the frame rate and does not change The overdrive value output before.

In some embodiments, the overdrive value used by the overdrive value generating unit 120 for the first frame data after the frame rate changes is the data corresponding to the changed frame rate, that is, the corresponding target overdrive value . However, when the frame rate changes too much, the target overdrive value and the frame rate The overdrive value before the rate change may be too different. In this case, if the target overdrive value corresponding to the changed frame rate is used directly to the first frame data after the frame rate changes, the overdrive value will be in a short time (here is a frame (Period) changes too much and affects the image display quality of the LCD panel.

Therefore, in order to avoid problems that affect the image display quality, in other embodiments, the overdrive value generation unit 120 gradually changes the overdrive value to the target overdrive value corresponding to the changed frame rate after the frame rate changes. In other words, the overdrive value generated by the overdrive value generation unit 120 for the first frame data after the frame rate changes gradually increases or decreases until the target overdrive value is reached.

The overdrive value may change linearly after the frame rate changes until the target overdrive value corresponding to the changed frame rate is reached. In detail, if the Nth frame of the overdrive value reaches the target overdrive value after the frame rate changes, the overdrive value corresponding to the i- th frame after the frame rate change is OD _O + _{[i (OD C -OD O)} / N], where i is a positive integer and less than or equal to N, OD _O is the overdrive value before the frame rate change, and OD _C is changed corresponding to the frame rate over the target Drive value.

It should be noted that the N value and the OD _C values based on characteristics of the liquid crystal display panel corresponding to the adjustment, for example, a liquid crystal display panel resolution, the number of pixels and the alignment unit types. In addition, according to different design and application requirements, in other embodiments, the overdrive value may be changed non-linearly after the frame rate is changed until the target overdrive value corresponding to the changed frame rate is reached.

Figure 2 illustrates the relationship between the frame number and the overdrive value when the frame rate changes. In this example, the overdrive value output by the overdrive value generating unit 120 in the ninth frame after the frame rate is changed is the target overdrive value, and the target overdrive value corresponding to the frame rate of 120 fps corresponds to 200. As shown in Figure 2, before the frame rate is changed, that is, when the frame rate is 60fps (60 frames per second), the overdrive value is 128; after the frame rate is increased to 120fps, the overdrive value is The frame unit is increased by 8, that is, the overdrive value of frame number FN+1 is increased to 136, the overdrive value of frame number FN+2 is increased to 144... and so on until the overdrive value of frame number FN+9 Drive value increased to 200.

Please refer to FIG. 3, which is a block diagram of overdrive value generation according to some embodiments of the present invention. The block diagram shown in FIG. 3 includes an overdrive value generation unit 310, a lookup table 320, and an overdrive value adjustment unit 330, which are used for overdrive processing of the liquid crystal display panel. In some embodiments, the overdriving process of the liquid crystal display panel is performed in the timing controller, that is, the overdriving value generating unit 310, the overdriving value adjusting unit 330, and the memory for storing the lookup table 320 are all located in the timing controller .

The overdrive value generating unit 310 receives the data of the two adjacent frames, and obtains the overdrive value of the data corresponding to the two adjacent frames according to the data in the lookup table 320. In detail, the data of the two frames are respectively the previous gray level value of the previous frame and the current gray level value of the current frame, and the overdrive value generating unit 310 looks up the corresponding previous gray level in the look-up table 320 Value and the overdrive value of this current grayscale value.

In addition, the overdrive value generating unit 310 also determines the first gain value according to the difference between the previous gray scale value and the current gray scale value, and according to the current gray scale value Determine the second gain value. After obtaining the first gain value and the second gain value, the overdrive value adjustment unit 330 then calculates the overdrive value and the first gain value and the second gain value obtained from the data in the lookup table 320, for example, the overdrive value Multiply the first gain value and the second gain value, and then update the overdrive value with the calculated result, and drive the liquid crystal display panel with the updated overdrive value.

In some embodiments, the overdriving value adjustment unit 330 only adjusts the overdriving value whose gray scale value change amount is lower. In other words, the overdrive value adjustment unit 330 only adjusts the corresponding overdrive value if the difference between the previous grayscale value and the current grayscale value is less than a threshold. For example, in a specific embodiment, the drive value generating unit 310 adjusts the corresponding overdrive value under the condition that the difference between the previous gray scale value and the current gray scale value is less than 32. The first gain value and the second gain value are both greater than 0 and less than or equal to 1, so that the updated drive value will be lower than the overdrive value in the lookup table 320. In this way, in the case where the gray scale value changes to a low degree, the liquid crystal display panel can be driven with a low overdrive value to prevent the light intensity of the liquid crystal display panel from changing too much, thereby improving the image display of the liquid crystal display panel quality.

It should be noted that the threshold, the first gain value and the second gain value can be adjusted according to the characteristics of the liquid crystal display panel, such as the number of gray scale bits of the liquid crystal display panel, resolution, number of unit pixels, alignment type and Frame rate, etc. For example, the above-mentioned adjustment method of the overdrive value can be applied to each pixel when the number of grayscale bits is 8 or 10 (that is, the grayscale value is 0 to 255 or 0 to 1023) The liquid crystal display panel, and/or the second gain value may be a concave function, a decreasing function, or an increasing function of the current gray scale value, but is not limited thereto.

In addition, in some embodiments, the difference between the previous gray-scale value and the current gray-scale value and the current gray-scale value may be interpolated, and the results of the interpolation operation correspond to specific first gain values and second gains, respectively. Value, which will be exemplified in subsequent paragraphs.

The following uses a 8-bit liquid crystal display device as an example to illustrate the block diagram of the overdrive value generation shown in FIG. 3. 4 is a schematic diagram of a lookup table according to some embodiments of the present invention. As shown in FIG. 4, the previous grayscale value and the current grayscale value are quantized values, and the difference between the previous grayscale value and the current grayscale value of the overdrive value generation unit 310 is not greater than 32 In the case of adjusting the overdrive value, this adjustment method will be exemplified in FIGS. 5 and 6. In contrast, in the case where the difference between the previous grayscale value and the current grayscale value is greater than 32, the overdrive value generating unit 310 can directly drive the liquid crystal display panel with the corresponding overdrive value stored in the lookup table 320 operating.

FIG. 5 is a table of correspondence between the difference between the previous gray level value Pre and the current gray level value Cur and the first gain value according to some embodiments of the present invention. In the table of FIG. 5, the difference between the previous gray level value Pre and the current gray level value Cur (ie △|Pre-Cur|) field has 9 preset values, and these preset values have corresponding The first gain value. In addition, FIG. 6 is a correspondence table between the current gray level value Cur and the second gain value according to some embodiments of the present invention. In the table of FIG. 6, the current grayscale value field has 9 preset values, and each of these preset values has a corresponding second gain value.

The over-driving value adjusting unit 330 may perform linear interpolation using the corresponding relationship tables in FIGS. 5 and 6 to obtain the first gain value and the second gain value. For example, if the previous gray scale value and the current gray scale value are 16 and 32 respectively, then according to the content shown in FIG. 5 and FIG. 6, the first gain value and the second gain value obtained by the overdrive value adjusting unit 330 are respectively 0.65 and 0.75; if the previous grayscale value and the current grayscale value are 38 and 48 respectively, then the first gain value and the second gain value obtained by the overdrive value adjustment unit 330 according to the content shown in FIG. 5 and FIG. 6 They are 2×0.75/4+2×0.7/4=0.725 and 16×0.75/32+16×0.875/32=0.8125. In addition, in other embodiments, the over-driving value adjustment unit 330 may use the correspondence tables in FIG. 5 and FIG. 6 to perform nonlinear interpolation operations.

It should be noted that the above contents shown in FIGS. 4 to 6 are only examples, which are not intended to limit the scope of the present invention. For example, the size of the lookup table 320 may be 33×33, and the difference field between the previous gray level value and the current gray level value or the current gray level value field may include 17 preset values, that is, preset values The number and/or spacing can be changed according to the design and application requirements. In addition, the correspondence tables shown in FIG. 5 and FIG. 6 can be stored in the memory of the timing controller together with the look-up table 320.

In summary, the overdriving method and timing driver of the present invention can improve the image display quality of the LCD panel when the frame rate changes and when the gray scale value changes.

Although the present invention has been disclosed as above with examples, it is not intended to limit the present invention. Any person with ordinary knowledge in the technical field of Without departing from the spirit and scope of the present invention, some changes and modifications can be made, so the scope of protection of the present invention shall be subject to the scope defined in the appended patent application.

110‧‧‧ Frame rate detection unit

120‧‧‧Overdrive value generating unit

130‧‧‧Look-up table

Claims (5)

An over-driving method is suitable for an LCD panel. The over-driving method includes: according to a previous gray scale value and a current gray scale value of the liquid crystal display panel, a previous gray scale value corresponding to the previous gray scale value is obtained from a look-up table And an overdrive value of the current grayscale value, wherein the difference between the previous grayscale value and the current grayscale value is less than or equal to 32; based on the difference between the previous grayscale value and the current grayscale value Determine a first gain value; determine a second gain value according to the current grayscale value; and perform an operation on the overdrive value, the first gain value, and the second gain value, and then update the Drive value, and drive the liquid crystal display panel with the updated overdrive value. The overdrive method as described in item 1 of the patent application range, wherein the previous gray scale value and the current gray scale value are positive integers greater than or equal to 0 and less than 2 ^N , where N is 8 or 10. The overdrive method as described in item 1 or 2 of the patent application range, wherein each of the first gain value and the second gain value is greater than 0 and less than or equal to 1. The overdriving method as described in item 1 or 2 of the patent application, wherein the second gain value is a concave function, a decreasing function, or an increasing function of the current gray-scale value. A timing controller suitable for an LCD panel. The timing controller includes: an overdrive value generating unit for obtaining a previous gray level value and a current gray level corresponding to the liquid crystal display panel from a look-up table One of the values is the overdrive value, and a first gain value is determined based on a difference between the previous grayscale value and the current grayscale value and a second gain value is determined based on the current grayscale value, wherein the previous grayscale value The difference between the level value and the current gray level value is less than or equal to 32; and an overdrive value adjustment unit for calculating the overdrive value, the first gain value and the second gain value, and then calculating The result of is to update the overdrive value, and the liquid crystal display panel is driven with the updated overdrive value.

Images